Combine the cornstarch, minced garlic, salt, 1 1/2 cups of flour, 2 teaspoons of paprika, and 2 teaspoons of ground black pepper in a mixing bowl; blend thoroughly then pour in the beer and stir until a smooth batter forms. For the seasoned flour, whisk together the garlic powder, cayenne pepper, remaining 2 cups of flour, 4 teaspoons of paprika, and the remaining 1/2 teaspoon of black pepper until well incorporated. Trim approximately 3/4 inch from the tops of the onions and remove the outer skins; slice each onion vertically into 12 to 16 sections, ensuring the root end remains intact. Carefully extract about 1 inch of petals from the center to create space for blooming, gently spreading the petals apart without tearing the onion. Dredge each onion in the seasoned flour, tapping away any excess; immerse them fully in the prepared batter, parting the petals so every layer is coated, then dredge again in the seasoned flour for an extra crispy finish. Heat oil in a deep fryer to a temperature between 375°F and 400°F; lower each onion gently into the basket and fry for approximately 1 1/2 minutes per side until deeply golden. Remove and allow to drain on paper towels. Serve immediately, positioned upright in a shallow dish; extract the central core using a circular cutter or apple corer if desired. Accompany with Bloomin’ Onion Sauce or Creamy Chili Sauce for dipping.